- Alien Sky: As Ryu approaches the gate to the Realm of Chaos in The Dark Sword of Chaos, he's greeted by an eerie violet sky with strange stars hanging too close to the surface.
- Attack Drone: The Shadow Clones from The Dark Sword of Chaos, which follow in Ryu's footsteps precisely and attack when he does, at no cost. He can have up to two clones out at a time.
- Back from the Dead: Irene after being sacrificed for Jacquio's goal in The Dark Sword of Chaos. She gets resurrected by the Dragon Sword's magic in the ending.
- Bait-and-Switch Gunshot: After beating first boss in The Dark Sword of Chaos, Dando the Cursed, Ryu meets a mysterious army operative who pulls a gun on him. Before Ryu can react, the man shoots...to finish off the monstrous Dando, who Ryu hadn't quite finished off.
- BFS: The titular Dark Sword of Chaos is just gigantic, yet Ashtar can wield it easily with one hand.
- "Blind Idiot" Translation: "Dando the Cursed" in The Dark Sword of Chaos is supposed to "The Damned One". This one is more forgivable, being an actual swear.
- Bloody Bowels of Hell: In The Dark Sword of Chaos, the last stages take place in the Realm of Chaos. They steadily become more organic, with pulsing organs and faces on the walls, dripping ooze, and veins running across every surface.
- Comic-Book Adaptation: The Nintendo Power Strategy Guide for The Dark Sword of Chaos followed the game's story between gameplay tips and tricks as a fully drawn comic book. Ryu's encounter with Ashtar◊ is a stand-out moment.
- Demoted to Extra: Clones of the Malice Four, the bosses of the first game, appear as powered-down mooks in the second game.
- Dramatic Thunder: The way that Ashtar introduces himself in The Dark Sword of Chaos.
- Evil Counterpart: As far as the NES games go, it's explicitly stated that the Dark Sword of Chaos is this to the Dragon Sword, having been forged from a demon's bones as opposed to a dragon's fang.
- Evil Tower of Ominousness: Both the Tower of Lahja, and later the gate to the Chaos Realm, in The Dark Sword of Chaos.
- Hellgate: The Dark Sword of Chaos presents a recursive example: an evil-looking tower with a demonic skull for an entrance, which leads to the antechamber of the Realm of Chaos. And inside that, an altar upon which the actual gates can be opened.
- Heroic Sacrifice: Back in The Dark Sword of Chaos, not only is it heavily implied that Robert died while he held the line to protect Ryu's back, but the Dragon Sword itself makes a sacrifice to revive Irene at the end.
- The Legions of Hell: What will pour out of the Gate of Darkness to the Realm of Chaos if Ashtar's ritual is completed. Many foes in the games already hail from there.
- Mask Power: Ashtar from The Dark Sword of Chaos wears a smooth, faceless metal mask with only thin slits for eyes... or maybe the eyes are part of the mask.
- Ninja Pirate Zombie Robot: Funky Dynamite, a man-sized mutant lizard cyborg with a jetpack and plasma guns.
Video Game / Ninja Gaiden II: The Dark Sword Of Chaos